# std::pmr::polymorphic_allocator<T>::allocate_bytes

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< cpp‎ | memory‎ | polymorphic allocator

void* allocate_bytes( std::size_t nbytes, std::size_t alignment = alignof(std::max_align_t) ); |  | (since C++20)

Allocates nbytes bytes of storage at specified alignment alignment using the underlying memory resource. Equivalent to return resource()->allocate(nbytes, alignment);.

### Parameters

nbytes | - | the number of bytes to allocate
alignment | - | the alignment to use

### Return value

A pointer to the allocated storage.

### Notes

This function was introduced for use with the fully-specialized allocator std::pmr::polymorphic_allocator<>, but it may be useful in any specialization.

The return type is void* (rather than, e.g., std::byte*) to support conversion to an arbitrary pointer type U* by static_cast<U*>.

### Exceptions

May throw any exceptions thrown by the call to resource()->allocate.

### See also

allocate_object (C++20) | allocates raw memory suitable for an object or an array (public member function)
new_object (C++20) | allocates and constructs an object (public member function)
allocate | allocate memory (public member function)
allocate [static] | allocates uninitialized storage using the allocator (public static member function of `std::allocator_traits<Alloc>`)
allocate | allocates memory (public member function of `std::pmr::memory_resource`)

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